1. Field of the Invention The invention relates to commercial and residential water heaters, and more particularly to an apparatus for cleaning such water heaters by the introduction of a stream of high-velocity water in a generally horizontal spray pattern across the bottom of the heater tank and the simultaneous opening of tank drain means diametrically opposed to the stream of water to permit removal of that foreign matter without the necessity of draining and refilling the tank.
2. Description of the Prior Art
A problem in the commercial and residential water heater industry is the accumulation of scale and other foreign matter along the bottom of water heater tanks. This accumulation of scale effectively shortens the life of such water heaters because the scale acts as an insulator, causing the tank metal to overheat and burn out. One device for cleaning water heaters is described in U.S. Pat. No. 4,263,879, issued to Lindahl on Apr. 28, 1981. Lindahl provides a tubular member along the bottom of and within a water heater tank. The tubular member has a plurality of small openings through which vertical and horizontal streams of water are directed upward and along the tank bottom. However, Lindahl merely appears to be directed to the prevention of settling of scale and other foreign matter on the bottom of the tanks. The Lindahl provisions for removal of solid materials from the tank do not include drain means or the like. Rather, the streams of water agitate and suspend the foreign matter within the heater, which is then passed out through the top of the tank along with the heated water.
U.S. Pat. No. 277,012, issued to Dinkel on May 8, 1833, discloses a substantially vertically-directed spray of a sugar-water solution to clean crystallized sugar crystals on tubes in a distillation apparatus. Dinken apparently does not disclose means for cleaning sediment at the bottom of a tank.
In contrast, U.S. Pat. Nos. 1,767,919 and 1,768,039, both issued to Eiermann on June 24, 1930; and U.S. Pat. No. 2,024,564, issued to Brand on Dec. 17, 1935, all disclose a means of cleaning the bottom of residential hot water tanks. However, each of these patents require that the tank first be drained, and then cleaned by introducing a cleaning spray from above and onto the bottom of the tank. For example, the Eiermann '919 reference discloses at page 2, lines 54-65, that although the inflow of water from the top of the cold water tube is usually sufficient to clean the bottom of the water heater, the removal of accumulated sediment should be effected by draining the heater, turning the water on so that it will spray the bottom of the heater, and then refilling the heater for normal operation. Similarly, the Eiermann '039 reference indicates at lines 68-85 substantially this same mode of operation. Finally, Brand indicates at p. 1, column 2, lines 14-16, that when it is desired to clean the heater, the water contained within that heater is drained off through a drain cock 16. Several other patents in the water heater or related arts include U.S. Pat. Nos. 641,295, issued to Jackson on Jan. 16, 1900; 1,028,180, issued to Bayer on June 4, 1912; 1,582,148, issued to Stockholder on Apr. 27, 1926; 1,696,005, issued to Kothe on Dec. 18, 1928; 2,137,253, issued to Thompson on Nov. 22, 1938; 2,290,368, issued to Dutton on July 21, 1942; and 4,527,543, issued to Denton on July 9, 1985.